Perspectives Commentary on: Results of Immunohistochemical Staining of Cell-Cycle Regulators: The Prediction of Recurrence of Functioning Pituitary Adenoma by Lee et al. pp. 563-575.
Griffith R. Harsh, IV, M.D. Professor, Department of Neurosurgery Stanford Hospitals and Clinics
Functional Pituitary Adenoma Recurrence After Surgical Resection Abdulrazag M. Ajlan and Griffith R. Harsh, IV
P
ituitary adenoma is the third most commonly diagnosed primary brain tumor after meningioma and glioma. Pituitary adenomas account for 14.1% of all primary intracranial neoplasms (4). Surgical resection is the preferred primary treatment for many pituitary adenomas. Up to one third of surgically resected tumors will recur, usually in the first 5 years after surgery (8). The indications for and preferred methods of treating recurrent pituitary adenomas vary with type of tumor. Either nonfunctional pituitary adenomas or functional (endocrinologically active) pituitary adenomas (FPA) may cause symptoms of mass effect at recurrence requiring treatment. The latter may need treatment for symptomatic elevated serum hormone levels regardless of tumor size, which may require further treatment. Predicting which pituitary tumors are more likely to recur is of extreme clinical importance in guiding the intensity of clinical, radiologic, and hormonal follow-up and the need for adjuvant therapy after surgical resection. Multiple attempts have been made during the past few decades to identify indicators of high risk of recurrence for pituitary tumors. Analyses of clinical, radiologic, histologic, immunocytochemical, and ultrastructural features have failed to reach consensus. The absence of a universally accepted classification of pituitary tumors is one challenge. The 2004 World Health Organization (WHO) classification of pituitary adenoma recognizes typical, atypical adenomas, and pituitary carcinomas (ICD-0 codes 8272/0, 8272/1, and 8272/3, respectively) (3). Adenomas are considered atypical if
Key words Cell cycle - Cyclin D1 - p16 - Pituitary adenoma - Recurrence - RB protein -
494
Abbreviations and Acronyms CDK: Cyclin-dependent kinase CI: Confidence interval FPA: Functional pituitary adenomas HR: Hazard ratio IHC: Immunohistochemical pRB: Phosphorylated retinoblastoma WHO: World Health Organization
www.SCIENCEDIRECT.com
one or more of the following features is observed: atypical morphologic features, increased mitotic activity, Ki-67 labeling index more than 3%, and extensive p53 immunoreactivity. The term pituitary carcinoma is reserved for adenomas with cerebrospinal and/or systemic metastasis. A recent retrospective analysis of 121 surgically treated pituitary adenomas showed an incidence of 15% of atypical, which is higher than in previous reports (10). The presence of atypical features correlated with a higher incidence of radiologically evident invasion of surrounding structures but not with recurrence in a relatively short follow-up period. Commonly available markers, such as mitotic count, Ki-67 mitotic index, and p53 immunoreactivity, are frequently reported to be associated with adenoma aggressiveness, but the lack of cutoff values and interlaboratory variability reduces their usefulness in predicting recurrence. Trouillas et al. (9) reported a multicenter case-control study of 410 surgically resected pituitary adenomas. In follow-up, patients with increased plasma hormone levels, recurrence, or progression were considered to have recurrent tumor during the relatively long follow-up period of 8 years. They assessed invasion on preoperative magnetic resonance imaging and/or histologically and measured the proliferative markers of the 2004 WHO classification (mitotic count, Ki-67 index, p53 positivity). Tumors were classified into five grades: grade 1a: (noninvasive tumor), grade 1b (noninvasive and proliferative tumor), grade 2a (invasive tumor), grade 2b (invasive and proliferative tumor), and grade 3 (metastatic tumor). Tumor
Department of Neurosurgery, Stanford Hospitals and Clinics, Stanford, California, USA To whom correspondence should be addressed: Abdulrazag M. Ajlan, M.B.B.S. [E-mail: [email protected]] Citation: World Neurosurg. (2014) 81, 3/4:494-496. http://dx.doi.org/10.1016/j.wneu.2013.11.001
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2013.11.001
PERSPECTIVES
grade was found to be associated with progression and/or recurrence at 8 years with an odds ratio of 12.09 (95% confidence interval [CI] 5.66; 25.81) for grade 2b tumors. This report emphasizes the importance of the clinicopathologic evaluation in the surgical management and follow-up of patients with pituitary adenoma. In addition to patient age, tumor size, and proliferation indices, the endocrinologic functional status of pituitary adenomas correlates with disease progression after surgical resection. A relation between functional status and risk of tumor progression has been inconsistently observed. A recent meta-analysis (8) showed that in long-term follow-up, prolactinmoas have a higher incidence of recurrence than functional adenomas but not nonfunctional adenomas. The same study identified the postoperative basal hormone level in functioning adenomas as the most important predictor of recurrence. In our experience, 23% (n ¼ 42/183 patients) of endoscopically resected adenomas involved the cavernous sinus. Cushing’s disease was the only statistically significant factor associated with cavernous sinus involvement. One third of the tumors with cavernous sinus invasion required further treatment compared with only 3% of the cases with no cavernous sinus involvement.
to identify the cut-point (value) of each marker above which positivity correlated with recurrence. The c2 test showed a statistically significant correlation between overstaining for p21, pRB, cyclin D1, MIB-1, mitotic count, and p53 and radiologic invasion of the cavernous sinus. Multivariate analysis using Cox’s proportional hazard regression model for recurrence after surgical resection showed that normal (below the cut-point) IHC staining for p16 (hazard ratio [HR] of 3.16, 95% CI 1.70e4.62; P < 0.001), IHC overstaining for pRB protein (HR 2.45, 95% CI 1.75e3.15; P ¼ 0.008), IHC overstaining for cyclin D1 (HR 2.13, 95% CI 1.33e2.93; P ¼ 0.029), and IHC overstaining for MIB-1 antigen (HR 2.74, P ¼ 0.002) were independently associated with high rate of recurrence. Among the other factors identified as predictive of recurrence were radiologic invasion (Knosp grade III-IV) (HR 4.02, 95% CI 2.69e5.35; P < 0.001) and mixed prolactin and growth hormone secretion (HR 2.08, P ¼ 0.032). For MIB-1, a rate of 2% was used as a cut-point for overstaining, versus the 3% used by WHO 2004.
The report by Lee et al. in this issue of WORLD NEUROSURGERY investigates the possible prognostic value of immunohistochemical (IHC) staining of selected cell-cycle proteins, MIB-1 antigen, and p53. In their retrospective analysis of 174 FPAs treated surgically, 35.6% recurred during the follow-up period (mean, 62.4 months; range, 24.2e118.9 months). An endoscopic endonasal approach was used in half of the patients. They included the IHC staining of the following cell-cycle regulatory proteins: p16, p15, p21, cyclindependent kinase (CDK) 4, CDK6, phosphorylated retinoblastoma (pRB) protein, and cyclin D1. These cell-cycle regulators have important roles in mitosis, with most acting as checkpoints during the progression from the G1 to the S phase (1, 2). CDK4-cyclin D and CDK6-cyclin D complexes are G1 phase regulators with active kinase function that modulates phosphorylation of the RB protein (1, 2). RB is a tumor suppressor protein that is active in the hypophosphorylated state. The phosphorylation of RB protein (inactive form) is an important step leading to progression from G1 to S phase. P16 (also known as INK4a or CDK inhibitor 2A), P15 (also known as INK4B4b or CDK4 inhibitor B), and P21 (also known as CDK inhibitor 1) regulate the cell cycle by inhibiting CDK activity (6).
The 2001 Nobel Prize in physiology or medicine was awarded to Leland Hartwell, R. Timothy Hunt, and Paul Nurse in recognition for their work identifying key molecules that regulate the cell cycle (6). Cell-cycle regulatory proteins and their roles in tumorigenesis have been investigated for more than two decades (7). Genetic or epigenetic changes in CDKs, their regulators, or upstream pathways alter the activity of cell-cycle regulators in cancer cells (7). The levels of expression of some cell-cycle regulators have been linked to aggressive behavior in some extracranial malignancies, but evidence for this is limited for pituitary tumors. Lee et al. used cellcycle regulatory proteins assessed by ICH technique to predict the recurrence of FPA after surgical resection. These markers can be added to the proliferative markers (MIB-1/Ki-67, p53, mitotic count) already being used to analyze surgically resected specimens in pituitary adenoma cases. Prospective analyses are required to validate these findings. A major limitation of this study is that recurrence was identified radiologically and trends of basal hormone levels were not reported. Lee et al. reported on the percentage of immunoreactivity measured by manual counting and that receiver operating characteristic-derived cut-points values do not eliminate interoperator variability. They state that their failure to study all cell-cycle regulator proteins may cause them to miss important interactions predicting recurrence, which is justified.
The IHC immunoreactivity, for all markers, counted the percentage of immunopositive cells identified by manual counting at high power magnification (400) in regions with the highest concentration of immunopositive nuclei. The threshold of immunoreactivity with the highest sensitivity and specificity was determined using receiver operating characteristic curve analysis (5). This was used
Identifying prospectively which pituitary adenomas are likely to recur after surgical resection would be a valuable guide to the follow-up and need for further treatment, especially for FPA. Prospective analysis may validate the use of IHC of some cellcycle regulatory proteins, in addition to the currently used Ki-67 labeling index, mitotic count, and p53, in predicting recurrence.
REFERENCES 1. Bertoli C, Skotheim JM, de Bruin RA: Control of cell cycle transcription during G1 and S phases. Nat Rev Mol Cell Biol 14:518-528, 2013. 2. Chulu JL, Liu HJ: Recent patents on cell cycle regulatory proteins. Recent Pat Biotechnol 3:1-9, 2009. 3. DeLellis RA, Lloyd RV, Heitz PU, Eng C, eds. World Health Organizationclassification of
tumours: tumours of endocrine organs. Lyons: IARC; 2004. 4. Dolecek TA, Propp JM, Stroup NE, Kruchko C: CBTRUS statistical report: primary brain and central nervous system tumors diagnosed in the United States in 2005e2009. Neuro Oncol 14(Suppl 5): v1-v49, 2012. 5. Eng J: Receiver operating characteristic analysis: a primer. Acad Radiol 12:909-916, 2005.
WORLD NEUROSURGERY 81 [3/4]: 494-496, MARCH/APRIL 2014
6. Garber K: Beyond the Nobel Prize: cell cycle research offers new view of cancer. J Natl Cancer Inst 93:1766-1768, 2001. 7. Malumbres M, Barbacid M: Cell cycle, CDKs and cancer: a changing paradigm. Nat Rev Cancer 9: 153-166, 2009. 8. Roelfsema F, Biermasz NR, Pereira AM: Clinical factors involved in the recurrence of pituitary adenomas after surgical remission: a structured review and meta-analysis. Pituitary 15:71-83, 2012.
www.WORLDNEUROSURGERY.org
495
PERSPECTIVES
9. Trouillas J, Roy P, Sturm N, Dantony E, CortetRudelli C, Viennet G, Bonneville JF, Assaker R, Auger C, Brue T, Cornelius A, Dufour H, Jouanneau E, Francois P, Galland F, Mougel F, Chapuis F, Villeneuve L, Maurage CA, FigarellaBranger D, Raverot G, Barlier A, Bernier M, Bonnet F, Borson-Chazot F, Brassier G, CauletMaugendre S, Chabre O, Chanson P, Cottier JF, Delemer B, Delgrange E, Di Tommaso L, Eimer S, Gaillard S, Jan M, Girard JJ, Lapras V, Loiseau H, Passagia JG, Patey M, Penfornis A, Poirier JY,
496
www.SCIENCEDIRECT.com
Perrin G, Tabarin A: A new prognostic clinicopathological classification of pituitary adenomas: a multicentric case-control study of 410 patients with 8 years post-operative follow-up. Acta Neuropathol 126:123-135, 2013.
10. Zada G, Woodmansee WW, Ramkissoon S, Amadio J, Nose V, Laws ER Jr: Atypical pituitary adenomas: incidence, clinical characteristics, and implications. J Neurosurg 114:336-344, 2011.
Citation: World Neurosurg. (2014) 81, 3/4:494-496. http://dx.doi.org/10.1016/j.wneu.2013.11.001 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2014 Elsevier Inc. All rights reserved.
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2013.11.001
Griffith R. Harsh, IV, M.D. Professor, Department of Neurosurgery Stanford Hospitals and Clinics
Functional Pituitary Adenoma Recurrence After Surgical Resection Abdulrazag M. Ajlan and Griffith R. Harsh, IV
P
ituitary adenoma is the third most commonly diagnosed primary brain tumor after meningioma and glioma. Pituitary adenomas account for 14.1% of all primary intracranial neoplasms (4). Surgical resection is the preferred primary treatment for many pituitary adenomas. Up to one third of surgically resected tumors will recur, usually in the first 5 years after surgery (8). The indications for and preferred methods of treating recurrent pituitary adenomas vary with type of tumor. Either nonfunctional pituitary adenomas or functional (endocrinologically active) pituitary adenomas (FPA) may cause symptoms of mass effect at recurrence requiring treatment. The latter may need treatment for symptomatic elevated serum hormone levels regardless of tumor size, which may require further treatment. Predicting which pituitary tumors are more likely to recur is of extreme clinical importance in guiding the intensity of clinical, radiologic, and hormonal follow-up and the need for adjuvant therapy after surgical resection. Multiple attempts have been made during the past few decades to identify indicators of high risk of recurrence for pituitary tumors. Analyses of clinical, radiologic, histologic, immunocytochemical, and ultrastructural features have failed to reach consensus. The absence of a universally accepted classification of pituitary tumors is one challenge. The 2004 World Health Organization (WHO) classification of pituitary adenoma recognizes typical, atypical adenomas, and pituitary carcinomas (ICD-0 codes 8272/0, 8272/1, and 8272/3, respectively) (3). Adenomas are considered atypical if
Key words Cell cycle - Cyclin D1 - p16 - Pituitary adenoma - Recurrence - RB protein -
494
Abbreviations and Acronyms CDK: Cyclin-dependent kinase CI: Confidence interval FPA: Functional pituitary adenomas HR: Hazard ratio IHC: Immunohistochemical pRB: Phosphorylated retinoblastoma WHO: World Health Organization
www.SCIENCEDIRECT.com
one or more of the following features is observed: atypical morphologic features, increased mitotic activity, Ki-67 labeling index more than 3%, and extensive p53 immunoreactivity. The term pituitary carcinoma is reserved for adenomas with cerebrospinal and/or systemic metastasis. A recent retrospective analysis of 121 surgically treated pituitary adenomas showed an incidence of 15% of atypical, which is higher than in previous reports (10). The presence of atypical features correlated with a higher incidence of radiologically evident invasion of surrounding structures but not with recurrence in a relatively short follow-up period. Commonly available markers, such as mitotic count, Ki-67 mitotic index, and p53 immunoreactivity, are frequently reported to be associated with adenoma aggressiveness, but the lack of cutoff values and interlaboratory variability reduces their usefulness in predicting recurrence. Trouillas et al. (9) reported a multicenter case-control study of 410 surgically resected pituitary adenomas. In follow-up, patients with increased plasma hormone levels, recurrence, or progression were considered to have recurrent tumor during the relatively long follow-up period of 8 years. They assessed invasion on preoperative magnetic resonance imaging and/or histologically and measured the proliferative markers of the 2004 WHO classification (mitotic count, Ki-67 index, p53 positivity). Tumors were classified into five grades: grade 1a: (noninvasive tumor), grade 1b (noninvasive and proliferative tumor), grade 2a (invasive tumor), grade 2b (invasive and proliferative tumor), and grade 3 (metastatic tumor). Tumor
Department of Neurosurgery, Stanford Hospitals and Clinics, Stanford, California, USA To whom correspondence should be addressed: Abdulrazag M. Ajlan, M.B.B.S. [E-mail: [email protected]] Citation: World Neurosurg. (2014) 81, 3/4:494-496. http://dx.doi.org/10.1016/j.wneu.2013.11.001
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2013.11.001
PERSPECTIVES
grade was found to be associated with progression and/or recurrence at 8 years with an odds ratio of 12.09 (95% confidence interval [CI] 5.66; 25.81) for grade 2b tumors. This report emphasizes the importance of the clinicopathologic evaluation in the surgical management and follow-up of patients with pituitary adenoma. In addition to patient age, tumor size, and proliferation indices, the endocrinologic functional status of pituitary adenomas correlates with disease progression after surgical resection. A relation between functional status and risk of tumor progression has been inconsistently observed. A recent meta-analysis (8) showed that in long-term follow-up, prolactinmoas have a higher incidence of recurrence than functional adenomas but not nonfunctional adenomas. The same study identified the postoperative basal hormone level in functioning adenomas as the most important predictor of recurrence. In our experience, 23% (n ¼ 42/183 patients) of endoscopically resected adenomas involved the cavernous sinus. Cushing’s disease was the only statistically significant factor associated with cavernous sinus involvement. One third of the tumors with cavernous sinus invasion required further treatment compared with only 3% of the cases with no cavernous sinus involvement.
to identify the cut-point (value) of each marker above which positivity correlated with recurrence. The c2 test showed a statistically significant correlation between overstaining for p21, pRB, cyclin D1, MIB-1, mitotic count, and p53 and radiologic invasion of the cavernous sinus. Multivariate analysis using Cox’s proportional hazard regression model for recurrence after surgical resection showed that normal (below the cut-point) IHC staining for p16 (hazard ratio [HR] of 3.16, 95% CI 1.70e4.62; P < 0.001), IHC overstaining for pRB protein (HR 2.45, 95% CI 1.75e3.15; P ¼ 0.008), IHC overstaining for cyclin D1 (HR 2.13, 95% CI 1.33e2.93; P ¼ 0.029), and IHC overstaining for MIB-1 antigen (HR 2.74, P ¼ 0.002) were independently associated with high rate of recurrence. Among the other factors identified as predictive of recurrence were radiologic invasion (Knosp grade III-IV) (HR 4.02, 95% CI 2.69e5.35; P < 0.001) and mixed prolactin and growth hormone secretion (HR 2.08, P ¼ 0.032). For MIB-1, a rate of 2% was used as a cut-point for overstaining, versus the 3% used by WHO 2004.
The report by Lee et al. in this issue of WORLD NEUROSURGERY investigates the possible prognostic value of immunohistochemical (IHC) staining of selected cell-cycle proteins, MIB-1 antigen, and p53. In their retrospective analysis of 174 FPAs treated surgically, 35.6% recurred during the follow-up period (mean, 62.4 months; range, 24.2e118.9 months). An endoscopic endonasal approach was used in half of the patients. They included the IHC staining of the following cell-cycle regulatory proteins: p16, p15, p21, cyclindependent kinase (CDK) 4, CDK6, phosphorylated retinoblastoma (pRB) protein, and cyclin D1. These cell-cycle regulators have important roles in mitosis, with most acting as checkpoints during the progression from the G1 to the S phase (1, 2). CDK4-cyclin D and CDK6-cyclin D complexes are G1 phase regulators with active kinase function that modulates phosphorylation of the RB protein (1, 2). RB is a tumor suppressor protein that is active in the hypophosphorylated state. The phosphorylation of RB protein (inactive form) is an important step leading to progression from G1 to S phase. P16 (also known as INK4a or CDK inhibitor 2A), P15 (also known as INK4B4b or CDK4 inhibitor B), and P21 (also known as CDK inhibitor 1) regulate the cell cycle by inhibiting CDK activity (6).
The 2001 Nobel Prize in physiology or medicine was awarded to Leland Hartwell, R. Timothy Hunt, and Paul Nurse in recognition for their work identifying key molecules that regulate the cell cycle (6). Cell-cycle regulatory proteins and their roles in tumorigenesis have been investigated for more than two decades (7). Genetic or epigenetic changes in CDKs, their regulators, or upstream pathways alter the activity of cell-cycle regulators in cancer cells (7). The levels of expression of some cell-cycle regulators have been linked to aggressive behavior in some extracranial malignancies, but evidence for this is limited for pituitary tumors. Lee et al. used cellcycle regulatory proteins assessed by ICH technique to predict the recurrence of FPA after surgical resection. These markers can be added to the proliferative markers (MIB-1/Ki-67, p53, mitotic count) already being used to analyze surgically resected specimens in pituitary adenoma cases. Prospective analyses are required to validate these findings. A major limitation of this study is that recurrence was identified radiologically and trends of basal hormone levels were not reported. Lee et al. reported on the percentage of immunoreactivity measured by manual counting and that receiver operating characteristic-derived cut-points values do not eliminate interoperator variability. They state that their failure to study all cell-cycle regulator proteins may cause them to miss important interactions predicting recurrence, which is justified.
The IHC immunoreactivity, for all markers, counted the percentage of immunopositive cells identified by manual counting at high power magnification (400) in regions with the highest concentration of immunopositive nuclei. The threshold of immunoreactivity with the highest sensitivity and specificity was determined using receiver operating characteristic curve analysis (5). This was used
Identifying prospectively which pituitary adenomas are likely to recur after surgical resection would be a valuable guide to the follow-up and need for further treatment, especially for FPA. Prospective analysis may validate the use of IHC of some cellcycle regulatory proteins, in addition to the currently used Ki-67 labeling index, mitotic count, and p53, in predicting recurrence.
REFERENCES 1. Bertoli C, Skotheim JM, de Bruin RA: Control of cell cycle transcription during G1 and S phases. Nat Rev Mol Cell Biol 14:518-528, 2013. 2. Chulu JL, Liu HJ: Recent patents on cell cycle regulatory proteins. Recent Pat Biotechnol 3:1-9, 2009. 3. DeLellis RA, Lloyd RV, Heitz PU, Eng C, eds. World Health Organizationclassification of
tumours: tumours of endocrine organs. Lyons: IARC; 2004. 4. Dolecek TA, Propp JM, Stroup NE, Kruchko C: CBTRUS statistical report: primary brain and central nervous system tumors diagnosed in the United States in 2005e2009. Neuro Oncol 14(Suppl 5): v1-v49, 2012. 5. Eng J: Receiver operating characteristic analysis: a primer. Acad Radiol 12:909-916, 2005.
WORLD NEUROSURGERY 81 [3/4]: 494-496, MARCH/APRIL 2014
6. Garber K: Beyond the Nobel Prize: cell cycle research offers new view of cancer. J Natl Cancer Inst 93:1766-1768, 2001. 7. Malumbres M, Barbacid M: Cell cycle, CDKs and cancer: a changing paradigm. Nat Rev Cancer 9: 153-166, 2009. 8. Roelfsema F, Biermasz NR, Pereira AM: Clinical factors involved in the recurrence of pituitary adenomas after surgical remission: a structured review and meta-analysis. Pituitary 15:71-83, 2012.
www.WORLDNEUROSURGERY.org
495
PERSPECTIVES
9. Trouillas J, Roy P, Sturm N, Dantony E, CortetRudelli C, Viennet G, Bonneville JF, Assaker R, Auger C, Brue T, Cornelius A, Dufour H, Jouanneau E, Francois P, Galland F, Mougel F, Chapuis F, Villeneuve L, Maurage CA, FigarellaBranger D, Raverot G, Barlier A, Bernier M, Bonnet F, Borson-Chazot F, Brassier G, CauletMaugendre S, Chabre O, Chanson P, Cottier JF, Delemer B, Delgrange E, Di Tommaso L, Eimer S, Gaillard S, Jan M, Girard JJ, Lapras V, Loiseau H, Passagia JG, Patey M, Penfornis A, Poirier JY,
496
www.SCIENCEDIRECT.com
Perrin G, Tabarin A: A new prognostic clinicopathological classification of pituitary adenomas: a multicentric case-control study of 410 patients with 8 years post-operative follow-up. Acta Neuropathol 126:123-135, 2013.
10. Zada G, Woodmansee WW, Ramkissoon S, Amadio J, Nose V, Laws ER Jr: Atypical pituitary adenomas: incidence, clinical characteristics, and implications. J Neurosurg 114:336-344, 2011.
Citation: World Neurosurg. (2014) 81, 3/4:494-496. http://dx.doi.org/10.1016/j.wneu.2013.11.001 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2014 Elsevier Inc. All rights reserved.
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2013.11.001
